Accommodating lens with haptics and toric surface

ABSTRACT

A flexible accommodating intraocular lens having anteriorly and posteriorly movable extended portions, such as T-shaped haptics, extending from a central solid biconvex optic to be implanted within a natural capsular bag of a human eye with the extended portions positioned between an anterior capsular rim and a posterior capsule of the bag, whereby during a post-operative healing period, fibrosis occurs about the extended portions to fixate the lens in the bag in a manner such that subsequent natural contraction and relaxation of the ciliary muscle moves the optic to provide vision accommodation. A surface of the optic is a toric surface.

[0001] This application is a continuation of application Ser. No.10/454,280, filed Jun. 3, 2003, which is a continuation of Ser. No.10/057,691, filed on Jan. 24, 2002, which is a division of applicationSer. No. 08/858,978, filed on May 20, 1997, now U.S. Pat. No. 6,387,126,which is a continuation-in-part of application Ser. No. 08/388,735,filed on Feb. 5, 1995, now abandoned, the disclosures of which areincorporated by reference.

BACKGROUND OF THE INVENTION

[0002] This invention relates generally to intraocular lenses to beimplanted within a natural capsular bag in the human eye formed byevacuation of the crystalline matrix from the natural lens of the eyethrough an anterior capsulotomy in the lens. The invention relates moreparticularly to novel accommodating intraocular lenses of this kindhaving improved features including an optic with a toric posteriorsurface.

[0003] The human eye has an anterior chamber between the cornea andiris, a posterior chamber behind the iris containing a crystalline lens,a vitreous chamber behind the lens containing vitreous humor, and aretina at the rear of the vitreous chamber. The crystalline lens of anormal human eye has a lens capsule attached about its periphery to theciliary muscle of the eye by zonules and containing a crystalline lensmatrix. This lens capsule has elastic optically clear anterior andposterior membrane-like walls commonly referred to by ophthalmologistsas anterior and posterior capsules, respectively. Between the iris andthe ciliary muscle is an annular crevice-like space called the ciliarysulcus.

[0004] The human eye in patients under the age of 45 years possessesnatural accommodation capability. Natural accommodation capabilityinvolves relaxation and contraction of the ciliary muscle of the eye bythe brain to provide the eye with near and distant vision. This ciliarymuscle action is automatic and shapes the natural crystalline lens tothe appropriate optical configuration for focusing on-the retina thelight rays entering the eye from the scene being viewed.

[0005] The human eye is subject to a variety of disorders which degradeor totally destroy the ability of the eye to function properly. One ofthe more common of these disorders involves progressive clouding of thenatural crystalline lens matrix resulting in the formation of what isreferred to as a cataract. It is now common practice to cure a cataractby surgically removing the cataractous human crystalline lens andimplanting an artificial intraocular lens in the eye to replace thenatural lens. The prior art is replete with a vast assortment ofintraocular lenses for this purpose.

[0006] Intraocular lenses differ widely in their physical appearance andarrangement. This invention is concerned with intraocular lenses of thekind having a central optical region or optic and portions which extendoutward from the optic and engage the interior of the eye in such a wayas to support the optic on the axis of the eye.

[0007] Intraocular lenses also differ with respect to theiraccommodation capability and their placement in the eye. Accommodationis the ability of an intraocular lens to accommodate, that is, to focusthe eye for near and distant vision. Certain patents describe allegedaccommodating intraocular lenses. Other patents describenon-accommodating intraocular lenses. Most non-accommodating lenses haveimmobile single focus optics which focus the eye at a certain fixeddistance only and require the wearing of eye glasses to change thefocus. Other non-accommodating lenses have bifocal optics whichsimultaneously image both near and distant objects on the retina of theeye. The brain selects the appropriate image and suppresses the otherimage, so that a bifocal intraocular lens provides both near vision anddistant vision sight without eyeglasses. Bifocal intraocular lenses,however, suffer from the disadvantage that each bifocal image representsonly about 40% of the available light, and a remaining 20% of the lightis lost in scatter.

[0008] There are four possible placements of an intraocular lens withinthe eye. These are (a) in the anterior chamber, (b) in the posteriorchamber, (c) in the capsular bag, and (d) in the vitreous chamber. Theintraocular lens disclosed herein is for placement in the capsular bag.

SUMMARY OF THE INVENTION

[0009] The present invention relates to accommodating intraocular lenseshaving a central optic and haptics, and wherein a surface, preferablythe posterior or back surface, of the optic is a toric surface.

[0010] This invention provides an improved accommodating intraocularlens to be implanted within a capsular bag of a human eye which remainsintact within the eye after removal of the crystalline lens matrix fromthe natural lens of the eye through an anterior capsule opening in thenatural lens. An improved accommodating intraocular lens according tothe invention includes a central optic having normally anterior andposterior sides and extended portions spaced circumferentially about andextending generally radially out from the edge of the optic.Importantly, the posterior or back surface of the optic is a toricsurface. These extended portions have inner ends joined to the optic andopposite outer ends movable anteriorly and posteriorly relative to theoptic. To this end, the extended portions may be either pivotally orflexibly hinged at their inner ends to the optic or are resilientlybendable throughout their length or may be relatively rigid. The terms“flex”, “flexing”, “flexible”, and the like are used in a broad sense tocover both flexibly hinged and resiliently bendable extended portions.The terms “hinge”, “hinged”, “hinging”, and the like are used in a broadsense to cover both pivotally and flexibly hinged extended portions.

[0011] The lens is surgically implanted within the evacuated capsularbag of a patient's eye through the anterior capsule opening in the bagand in a position wherein the lens optic is aligned with the opening,and the outer ends of the lens extended portions are situated within theouter perimeter or cul-de-sac of the bag. The lens has a radialdimension from the outer end of each extended portion to the axis of thelens optic such that when the lens is implanted within the capsular bag,the outer ends of the extended portions engage the inner perimetricalwall of the bag without unnecessarily stretching the bag.

[0012] As is known, after surgical implantation of the accommodatingintraocular lens in the capsular bag of the eye, active endodermal cellson the posterior side of the anterior capsule rim of the bag causefibrosis with shrinkage of the bag and fusion of the rim to the elasticposterior capsule of the bag. This fibrosis occurs about the lensextended portions in such a way that these extended portions and thelens are effectively “shrink-wrapped” by the fibrous tissue in such away as to form radial pockets in the fibrous tissue which contain theextended portions with their outer ends positioned within the outercul-de-sac of the capsular bag. The lens is thereby fixated within thecapsular bag with the lens optic aligned with the anterior capsuleopening in the bag. The anterior capsule rim shrinks during fibrosis,and this shrinkage combined with shrink-wrapping of the extendedportions causes some radial compression of the lens in a manner whichtends to move the lens optic relative to the outer ends of the extendedportions posteriorly along the axis of the eye. The fibrosed,leather-like anterior capsule rim prevents anterior movement of theoptic and urges the optic rearwardly during fibrosis. Accordingly,fibrosis induced movement of the optic occurs posteriorly to a distantvision position in which either or both the optic and the inner ends ofthe extended portions press rearwardly against the elastic posteriorcapsule of the capsular bag and stretch this posterior capsulerearwardly.

[0013] During surgery, the ciliary muscle of the eye is paralyzed with aciliary muscle relaxant, i.e. a cycloplegic, to place the muscle in itsrelaxed state. Following surgery, a ciliary muscle relaxant, acycloplegic, is introduced into the eye to paralyze the ciliary musclethroughout the post-operative fibrosis and healing period (from two tothree weeks) to maintain the ciliary muscle in its relaxed state untilfibrosis is complete. This drug-induced relaxation of the ciliary muscleprevents contraction of the ciliary muscle and immobilizes the capsularbag during fibrosis. By this means, the lens optic is fixed duringfibrosis in its distant vision position within the eye relative to theretina wherein the lens presses rearwardly against and therebyposteriorly stretches the elastic posterior capsule of the capsular bag.If the ciliary muscle was not thus maintained in its relaxed state untilthe completion of fibrosis, the ciliary muscle would undergo essentiallynormal brain-induced vision accommodation contraction and relaxationduring fibrosis. This ciliary muscle action during fibrosis would resultin improper formation of the pockets in the fibrosis tissue whichcontain the extended portions of the lens. Moreover, ciliary musclecontraction during fibrosis would compress the capsular bag and therebythe lens radially in such a way as to very likely dislocate or decenterthe lens from its proper position in the bag or fix the optic in thenear vision position.

[0014] When the cycloplegic effect of the ciliary muscle relaxant wearsoff after the completion of fibrosis, the ciliary muscle again becomesfree to undergo normal brain-induced contraction and relaxation. Normalbrain-induced contraction of the muscle then compresses the lensradially, relaxes the zonules and anterior capsule rim, and increasesvitreous pressure in the vitreous cavity of the eye. This normalcontraction of the ciliary muscle effects anterior accommodationmovement of the lens optic for near vision by the combined action of theincreased vitreous pressure, anterior capsule rim relaxation, and theanterior bias of the stretched posterior capsule. Similarly,brain-induced relaxation of the ciliary muscle reduces vitreouspressure, relieves radial compression of the lens, and stretches theanterior capsule rim to effect posterior movement of the lens optic fordistant vision.

[0015] Normal brain-induced contraction and relaxation of the ciliarymuscle after the completion of fibrosis thus causes anterior andposterior accommodation movement of the lens optic between near anddistant vision positions relative to the retina. During thisaccommodation movement of the optic, the lens extended portions mayundergo endwise movement within their pockets in the fibrous tissue.

[0016] The described lens embodiments of the invention conform to one ofthe following basic lens configurations:

[0017] A. A flexible lens body configuration wherein the extendingportions and optic are all flexible and the extending portions and opticare in the same plane. This lens after implantation in the eye and afterparalyzing the ciliary muscle for two to three weeks, undergoes naturalposterior location in the capsular bag space due to end-wise compressionand shrink-wrapping of the lens by fibrosis of the anterior capsule.

[0018] B. A lens configuration such that the lens body is flexiblethroughout the extending portions and optic such that the lens opticbefore implantation is located behind the outer ends of the extendingportions such that the optic can move backwards and forwards along theaxis of the eye relative to the outer ends of the haptics. This movementcan be such that the optic never moves anteriorly to the outer ends ofthe extending portions, that it moves from a posterior position to aposition which makes it uniplanar to the outer ends of the extendingportions, or such that it moves from a posterior position to a positionanterior to the outer ends of the extending portions.

[0019] C. An accommodating flexible intraocular lens whereby theextended portions and optic are flexible, wherein the optic is locatedanteriorly to the outer ends of the extended portions prior toimplantation within the eye. The lens is configured such that, withconstriction of the ciliary muscle, the optic will move anteriorlyrelative to the outer ends of the extended portions and posteriorly uponrelaxation of the ciliary muscle relative to the outer end of theextended portions. The optic may or may not move to the same plane as orbehind the outer ends of the extended portions. The three embodimentsdescribed above may have a reduced thickness portion of the extendedportion adjacent to the optic comprising a thinned portion or a groove,or the extended portions adjacent to the optic may be resilientlyflexible without having a hinged or thin portion. Should the materialfrom which the lens is made be relatively rigid, then the whole lensitself may move backwards and forwards without there being any flexionat the optic flexible portion junction. The movement of the lens aloneor the lens optic relative to the outer ends of the extended portionsmay be caused by one or a combination of the following: constriction andrelaxation of the ciliary muscle, increase and decrease of vitreouscavity pressure, the resilience of the posterior capsule, and end-wisecompression and relaxation of the lens by the ciliary muscle through thecapsular bag wall.

[0020] The extended portions of a presently preferred lens embodimentare generally T-shaped haptics each including a haptic plate and a pairof relatively slender resiliently flexible fixation fingers at the outerend of the haptic plate. In their normal unstressed state, the twofixation fingers at the outer end of each haptic plate extend laterallyoutward from opposite edges of the respective haptic plate in the planeof the plate and substantially flush with the radially outer end edge ofthe plate to form the horizontal “crossbar” of the haptic T-shape. Theradially outer end edges of the haptic plates are circularly curvedabout the central axis of the lens optic to substantially equal radiiclosely approximating the radius of the interior perimeter of thecapsular bag when the ciliary muscle of the eye is relaxed. Duringimplantation of the lens in the bag, the inner perimetrical wall of thebag deflects the haptic fingers generally radially inward from theirnormal unstressed positions to arcuate bent configurations in which theradially outer edges of the fingers and the curved outer end edges ofthe respective haptic plates conform approximately to a common circularcurvature closely approximating the curvature of the inner perimetricalwall of the bag. The outer T-ends of the haptics then press lightlyagainst the perimetrical bag wall and are fixated within the bagperimeter during fibrosis with approximation of the anterior capsule tothe posterior capsule to accurately center the implanted lens in the bagwith the lens optic aligned with the anterior capsule opening in thebag.

[0021] The haptic plates of certain described lens embodiments arenarrower in width than the optic diameter and are tapered so as tonarrow in width toward their outer ends. These relatively narrow platesof the haptics flex or pivot relatively easily to aid the accommodatingaction of the lens and form haptic pockets of maximum length in thefibrous tissue between the haptic fingers and the optic which maximizethe accommodation movement of the lens optic. The tapered haptics, beingwider adjacent to the optic, can slide radially in the capsular bagpockets during contraction of the ciliary muscle to enable forwardmovement of the optic for vision accommodation.

[0022] In a lens embodiment of the invention, the lens optic andextended portions, which may be plates, are molded or otherwisefabricated preferably as an integral one piece lens structure in whichthe inner ends of the extended portions are integrally joined to theoptic, and the extended portions have flexible hinges at their innerends adjacent the optic at which the extended portions are hingableanteriorly and posteriorly relative to the optic. The extended portionsare T-shaped haptics formed by embedding flexible haptic fingers onloops with the haptic plates proper. In particular, the optic has atoric posterior surface.

[0023] Accordingly, it is a principal object of the present invention toprovide an improved toric accommodating lens.

BRIEF DESCRIPTION OF THE DRAWINGS

[0024]FIG. 1 is a plan view of the lens according to the presentinvention,

[0025]FIG. 2 is a side view thereof, and

[0026]FIG. 3 is a view showing the lens as implanted.

[0027]FIG. 4 is a view showing a plate embodiment of the toric lens.

[0028]FIG. 5 is a view of a lens with multi extended portions.

[0029]FIG. 6 is an alternative embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0030] Turning now to the drawings and first to FIG. 3, the capsular bag(not shown) includes an annular anterior capsular remnant or rim 22. Thecapsular rim 22 is the remnant of the anterior capsule of the naturallens which remains after capsulorhexis has been performed on the naturallens. This rim circumferentially surrounds a central, general roundanterior opening 26 (capsulotomy) in the capsular bag through which thenatural lens matrix was previously removed from the natural lens. Thecapsular bag is secured about its perimeter to the ciliary muscle viathe zonules which are not shown.

[0031] Implanted within the capsular bag of the eye is an accommodatingintraocular lens 32 according to this invention which replaces andperforms the accommodation function of the removed human crystallinelens. The accommodating intraocular lens may be utilized to replaceeither a natural lens which is virtually totally defective, such as acataractous natural lens, or a natural lens that provides satisfactoryvision at one distance without the wearing of glasses but providessatisfactory vision at another distance only when glasses are worn. Forexample, the accommodating intraocular lens of the invention can beutilized to correct refractive errors and restore accommodation forpersons in their mid-40s or older who require reading glasses orbifocals for near vision.

[0032] Intraocular lens 32 comprises a flexible unitary lens body,including a flexible biconvex solid optic 34, which may be formed ofrelatively hard material, relatively soft flexible semi-rigid material,or a combination of both hard and soft materials. Examples of relativelyhard materials which are suitable for the lens body are methylmethacrylate, polysulfones, and other relatively hard biologically inertoptical materials. Examples of suitable relatively soft materials forthe lens body are silicone, hydrogels, thermolabile materials, and otherflexible semi-rigid biologically inert optical materials.

[0033] The lens 32 includes the central optic 34 and T-shaped extendedportions or plate haptics 36 extending from diametrically opposite edgesof the optic. Importantly, the posterior surface 34 b (FIG. 2), is atoric surface and the anterior surface 34 a may have any suitablecurvature such as spherical. The toric surface 34 b may be on either theposterior or anterior surface and allows for correction of astigmatism.Since the toric surface is irregular as contrasted to a sphericalsurface, the lens can include some indicia to facilitate properinsertion and orientation in the eye. The fingers 36 b preferably haveenlarged ends 36 c as seen in FIG. 1.

[0034] The haptics include haptic members or plates 36 a having innerends joined to the optic and opposite outer free ends and lateralfixation fingers or loops 36 b at their outer ends. The loops 36 b areattached at 36 d (like arrow heads) to the outer ends of the plates 36a. The loops 36 b may be of a different but flexible material.

[0035] The haptic plates 36 a preferably are longitudinally tapered soas to narrow in width toward their outer ends and may have a widththroughout their length less than the diameter of the optic 34, and maybe resiliently flexible for major portions of their lengths. The haptics36 are movable anteriorly and posteriorly relative to the optic 34, thatis to say the outer ends of the haptics are movable anteriorly andposteriorly relative to the optic. The preferred lens embodimentillustrated is constructed of a resilient semi-rigid material and hasflexible hinges 38 which join the inner ends of the haptic plates 36 ato the optic. The haptics are relatively rigid and are flexible aboutthe hinges anteriorly and posteriorly relative to the optic as shown inFIGS. 1 and 2. These hinges are formed by grooves 40 which can be eitheron the anterior, posterior, or both sides and extend across the innerends of the haptic plates 36 a. In the present preferred embodiment thegrooves 40 are in the anterior side as seen in FIG. 2. The haptics 36are flexible about the hinges 38 in the anterior and posteriordirections of the optic. The lens has a relatively flat unstressedconfiguration, illustrated in FIG. 2 wherein the haptics 36 and theirhinges 38 are disposed in a common plane transverse to the optic axis ofthe optic 34. Deformation of the lens from this normal unstressedconfiguration by anterior or posterior deflection of the haptics abouttheir hinges creates in the hinges elastic strain energy forces whichurge the lens to its normal unstressed configuration. The outer endedges 41 of the haptic plates 36 a are preferably slightly curved aboutthe optic axis of the optic 34, as shown in FIG. 1. In their normalunstressed state shown in solid lines in FIG. 1, the fixation loops 36 bof each plate haptic 36 extend laterally out from opposite longitudinaledges of the respective haptic plate 36 a in the plane of the plate andsubstantially flush with the outer end edge 41 of the plate. Whenunstressed, the loops 36 b are preferably straight or slightly bowedwith a slight radially inward curvature, as shown in solid lines inFIG. 1. As shown in broken lines in FIG. 3, the loops 36 b are laterallyresiliently flexible radially of the haptic plates 36 a to their brokenline positions of FIG. 3 in which the radially outer edges of thefingers and the end edges 41 of the haptic plates 36 a conformsubstantially to a common circle centered on the axis of the optic 34.

[0036] An accommodating toric intraocular lens 52 according to FIG. 4which comprises a biconvex solid optic 54 with plate extending portions56, having raised shoulders 58 on one or both sides at the distal endsof the extended portions. The extending portions 54 may have a groove orhinge 55 across their surfaces adjacent to the optic or may beresiliently flexible at the juncture of the optic and extended portions.

[0037]FIG. 5 illustrates an accommodating toric intraocular lens 62which has an optic 64 and four extending portions 66, which in thisinstance comprise plates with fixation centration devices 69 at theirdistal ends. These fixation devices may comprise raised shoulders 68 onone or both sides of the extended portions 66. The junction of theextended portions, which may be plates, has a thinned area or a groove65 adjacent to the optic 64 or may just be resiliently flexible at thejunction of the plate extended portion to the optic.

[0038]FIG. 6 illustrates an alternative embodiment of a lens 70 whereinthe extending portions or haptics are in the form of thin members 72extending from the optic 74. Centration/fixation loops 80 can be addedto both outer ends or not added as desired, and likewise hinges 75 asshown can be provided on both sets of haptics or omitted from both asdesired. Furthermore, knobs 78 can be provided at the ends of loops 80or omitted. While embodiments of the present invention have been shownand described, various modifications may be made without departing fromthe scope of the present invention, and all such modifications andequivalents are intended to be covered.

What is claimed is:
 1. An accommodating intraocular lens wherein thelens comprises a flexible lens body having normally anterior andposterior sides, including a flexible solid biconvex optic, said lensbody having two or more radially extending portions from the optic suchthat the lens can move anteriorly with contraction of the ciliary bodyof the eye, the optic having a toric surface, and the lens being sizedto be implanted into the capsular bag of the eye such that contractionof the ciliary muscle causes the lens within the capsular bag behind theiris to move forward towards the iris.
 2. An accommodating lensaccording to claim 1 wherein the lens is sized to not be in contact withthe ciliary muscle through the capsular bag wall,
 3. An accommodatinglens according to claim 1 wherein the lens is sized to be in contactwith the ciliary muscle through the capsular bag wall.
 4. Anaccommodating lens according to claim 1 wherein the lens can moveanteriorly and posteriorly.
 5. An accommodating lens according to claim1, wherein the outer ends of the extending portions can move anteriorlyand posteriorly relative to the optic.
 6. An accommodating lensaccording to claim 1, wherein internal elastic strain causes the lens tomove anteriorly.
 7. An accommodating lens according to claim 1, whereinposterior capsule elasticity causes the lens to move anteriorly.
 8. Anaccommodating lens according to claim 1, wherein the optic can moveforward and backwards with ciliary muscle contraction and relaxation. 9.An accommodating lens according to claim 7 wherein the optic can movealong the axis of the eye relative to the outer ends of the extendingportions.
 10. An accommodating lens according to claim 1, which isuniplanar.
 11. An accommodating lens according to claim 1, which isvaulted forward.
 12. An accommodating lens according to claim 1, whichis vaulted backward.
 13. An accommodating lens according to claim 1,which is multiplanar.
 14. An accommodating lens according to claim 1,with the extending portions and optic are made from different materials.15. An accommodating lens according to claim 1, wherein the extendingportions are plate haptics.
 16. An accommodating lens according to claim1, wherein the extended portions are plate haptics with hinges.
 17. Anaccommodating lens according to claim 1, wherein constriction of theciliary muscle can produce forward movement of the lens optic within thecapsular bag towards the iris for near vision.
 18. An accommodating lensaccording to claim 1, wherein the extending portions are plate hapticswith a groove across each plate haptic adjacent the optic.
 19. Anaccommodating lens according to claim 1, wherein the extending portionsare plate haptics with raised shoulders at their outer ends on either orboth surfaces.
 20. An accommodating lens according to claim 1, whereintwo or more extending portions comprise plate haptics with a grooveacross the plate haptic adjacent to the optic.
 21. An accommodating lensaccording to claim 1, wherein the extending portions have knobs at thecorners of the distal ends.
 22. An accommodating lens according to claim1, wherein two or more extending portions have lateral fixation deviceswhich comprise loops.
 23. An accommodating lens according to claim 1,wherein the extending portions include hinged plate haptics withlaterally extending flexible fixation fingers.
 24. An accommodating lensaccording to claim 1, wherein the lens has extended hinged portionscomprising plate haptics which include laterally extending flexiblefixation fingers at their outer ends which are made of materialdifferent from that of the haptic plates.
 25. An accommodating lensaccording to claim 1, wherein the optic is located posteriorly to theouter ends of the extending portions.
 26. An accommodating lensaccording to claim 1, wherein the extending portions comprise platehaptics which have one or more resilient springs at their distal ends.